Doctor Who, the television programme and larger franchise. By far, the more dominant, public rendering of the franchise name is Doctor Who, but the contraction has appeared with regularity on internal BBC documents. It has also been used often in TV listings around the world, merely because it's shorter than the full name and will fit into a smaller space.

Dr. Who (memo), known more completely as "Dr. Who: General Notes on Background and Approach for an Exciting Adventure - Science Fiction Drama Series for Childrens Saturday Viewing", the original pitch for Doctor Who